Create a translucent plastic node setup/bump map for "ice pack" material
This should be rather simple. Just use a noise texture (softened by runiing through a MixRGB with white) and a Bump Node to get the surface bumps. Then, create the &quot;icy&quot; (translucent) gel effect by using a small Subsurface Value (0.3) and a blue color.

If you want to go deeper on the gel effect, try increasing the blue and green values only of your Subsurface Radius: